List Methods Guide

Here are a few useful list methods that work on list objects in Python. For a full list of list methods, refer to the Python reference here: Python Reference List.

• append(element):
  • Description: Adds an element to the end of the list.
  • Parameters:
    • element: The element to add to the list.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    fruits.append("orange")
    print(fruits)  # Outputs: ['apple', 'banana', 'cherry', 'orange']
    

• extend(iterable):
  • Description: Extends the list by appending all the elements from another iterable (e.g., another list).
  • Parameters:
    • iterable: Any iterable (like a list or tuple) whose elements will be added to the list.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    more_fruits = ["mango", "pineapple"]
    fruits.extend(more_fruits)
    print(fruits)  # Outputs: ['apple', 'banana', 'cherry', 'mango', 'pineapple']
    

• insert(index, element):
  • Description: Inserts an element at a specified position.
  • Parameters:
    • index: The position where the element should be inserted.
    • element: The element to insert into the list.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    fruits.insert(1, "orange")
    print(fruits)  # Outputs: ['apple', 'orange', 'banana', 'cherry']
    

• remove(element):
  • Description: Removes the first occurrence of a specified element from the list.
  • Parameters:
    • element: The element to be removed.
  • Example:

    fruits = ["apple", "banana", "cherry", "banana"]
    fruits.remove("banana")
    print(fruits)  # Outputs: ['apple', 'cherry', 'banana']
    

• pop(index):
  • Description: Removes and returns the element at a specified position. If no index is specified, removes the last element.
  • Parameters:
    • index (optional): The index of the element to remove. Defaults to the last item if not specified.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    fruit = fruits.pop(1)
    print(fruit)  # Outputs: 'banana'
    print(fruits)  # Outputs: ['apple', 'cherry']
    

• index(element):
  • Description: Returns the index of the first occurrence of a specified element in the list. If the element is not found, it raises a ValueError.
  • Parameters:
    • element: The element whose index needs to be found.
    • start (optional): The position to start the search. Defaults to the beginning of the list.
    • end (optional): The position to end the search. Defaults to the end of the list.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    position = fruits.index("banana")
    print(position)  # Outputs: 1
    

• count(element):
  • Description: Returns the number of times the specified element appears in the list.
  • Parameters:
    • element: The element whose occurrences need to be counted.
  • Example:

    fruits = ["apple", "banana", "cherry", "banana"]
    count_bananas = fruits.count("banana")
    print(count_bananas)  # Outputs: 2
    

• sort():
  • Description: Sorts the list in ascending order. If reverse=True is specified, sorts in descending order.
  • Parameters:
    • key (optional): A function that serves as a key for the sort comparison.
    • reverse (optional): If True, sorts the list in descending order. Defaults to False.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    fruits.sort()
    print(fruits)  # Outputs: ['apple', 'banana', 'cherry']
    fruits.sort(reverse=True)
    print(fruits)  # Outputs: ['cherry', 'banana', 'apple']
    

• reverse():
  • Description: Reverses the elements of the list in place.
  • Parameters: This method does not take any parameters.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    fruits.reverse()
    print(fruits)  # Outputs: ['cherry', 'banana', 'apple']
    

• clear():
  • Description: Removes all elements from the list, leaving it empty.
  • Parameters: This method does not take any parameters.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    fruits.clear()
    print(fruits)  # Outputs: []
    

• copy():
  • Description: Returns a shallow copy of the list.
  • Parameters: This method does not take any parameters.
  • Example:

    fruits = ["apple", "banana", "cherry"]
    fruits_copy = fruits.copy()
    print(fruits_copy)  # Outputs: ['apple', 'banana', 'cherry']